IS) 
Us 
ress, 
  
-20 
n "he cosh of Lhe equipment — depending on Lype of system and Lype 
of aircraft — lies between 2% and 20% of the "total flight system" 
cost. 
In comparison to the high potential benifits in the macro-economy 
of projects, these costs are relatively low. 
The new possibilities may allow for remarkable "cost/henifit" 
o) 
ratios. 
n It is high time that aerial surveyors investigate the possibilities 
which are available now. 
8 Examples of open questions: 
a 
e. 
Modern equipment can determine and record the positions and attitudes of the aerial cameras and sensors at each 
instant of exposure and sensing. They can present the six orientation elements at each exposure station, in the eir, 
not image coordinates or terrain coordinates. 
Question: How to convert these orientation elements into coordinates of recognisable ground features? 
. The use of the orientation elements recorded during flight might reduce the amount of ground control which is needed, 
and/or it might simplify photogrammetric methods and/or instruments. 
Question: How can ground control economy be improved and how can photogrammetry be simplified when using the 
modern posibilities? 
In reasonably flat terrain, the recording of position coordinates, height, azimuth and verticality may enable to 
have available individual semi-controlled photomap sheets, the day after the photo flight. 
Question: What is the degree of usefulness of this possibility, in the macro-economy of development projects? 
For ortho-photo-mapping, the photographs can be pre-planned and pre-programmed in pin-pointed symphotblocks to 
produce the "one photo = one map sheet” situation. 
m Qguestion: What is the degree of usefulness in terms of saving cartographic effort in ortho-photo-mapping? 
In ortho-photo-mapping, the records of the six elements of orientation for each photograph might produce the 
orthophotomodel orientation immediately. In addition, in case digital terrain models (DM's) would be available, 
these could be incorporated in the orthophotomapping procedure. 
Question: Which methods and combinations of methods can be designed to fully utilize the new possibilities? 
o) See: F.L.J.H. Corten, Economy in aerial survey by means of the ITC 
Photnav System, ISP Commission IV, presented paper at Helsinki 
Congress, 1976.